Management of permanent set-aside on arable land in Sweden

1, Set-aside fields have been an important element of the European agricultural landscape since the introduction of the set-aside scheme by the European Community. However, countries in the European Community differ in their rules for managing set-aside owing to different priorities. 2, In Sweden, a major goal is to reduce the total use of agricultural pesticides, consequently their use is prohibited in set-aside. The options for weed control are therefore cutting and/or the use of a cover crop. 3, In this study, we describe the course of succession following the abandonment of farmland managed in different ways. The floristic composition was followed over a 10-year period. Temporal trends in community development are described. 4. The experiment began in 1975 on farmland at six localities, distributed from southern to northern Sweden. The management treatments involving the application of fertilizers and cutting were applied to plots sown with a cover crop and to plots in which the succession started from bare ground. 5, We found that competitive interactions between species largely determined the successional course in our study. The competitive success of species was related to the management practices applied but there were also interactions between management and site conditions. 6. We propose that natural succession can be recommended on poor sites in combination with cutting, mainly to prevent the invasion of woody species. On fertile sites a cover crop should be used to suppress perennial weeds, and cutting is recommended mainly to increase species diversity.